Automatic humidity and temperature control



May 11 1926.

. R, CARLSTEDT AUTOMATIC HUMIDITY AND TEMPERATURE CONTROL Filed June 19, 1924 Patented May 11, 1926. it

UNI D STATES 'R/ A.GN'AR oA Ls EnT, E sTocKHoLM, SWEDEN, ASSIGNOR To ARcA REGULATORS PATENT OFFICE.

INCORPORATED, A CORPORATION OF VIRGINIA.

AU omATIc HUMIDITY AND TEMPERATURE CONTROL.

Application filed June19, 1924. Serial No. 721,104.

The present invention relates to an apparatus for conditioning air, and has for its purpose to maintain a definite relation between temperature and humidity and to provide novel means for controlling humidity.

The invention isparticularly applicable to drying rooms where a fixed temperature and fixed humidity is necessary. For example, in the tobacco industry, up to the present time it has been impossible to regulate the moisture content and temperature in drying rooms in a satisfactory manner, there being no sufliciently sensitive apparatus for this purpose.

The invention is more fully decribed in connection with the accompanying drawing on which Fig. 1 shows a drying chamber with my invention applied thereto. Fig. 2

shows details of construction of the apparatus shown in Fig. 1.

In Fig. 1, 2 is a drying room, through which air is drawn by the fan 3 which is driven by electric motor 4. At the inlet 5 this air passes a heating element 6 by means of which it is heated to a definite temperature. Arranged. in the chamber is a socalled humidity relay 7, shown on an enlarged scale in Fig. 2, consisting of a throttling lever 8 which is movable in front of a 0 nozzle through which a continuously flowing stream of liquid issues and which is connected by means of the pipe 10 with operating mechanism for a servo-motor 11 actuated by a pressure fluid which servo-motor in its 2 turn adjusts a rheostat 12 by which the speed of the motor 4 is varied. This throttling lever is connected with a member 14, which preferably consists of several united parallel cotton threads, adjustably suspended .at the point 15 by means of a. screw 26. The throttling lever 8,'which for the purpose of moving with the least possible friction is journaled on points 16, is also influenced by a spring 17 which is tensed to a greater or less degree by means of the screw 18.

Servo-motor 11' consists of a piston 21 to" which is atta'cliedpiston rod 23. A flexible member 22, .such as a chain, is connected at one end of the piston rod 23 and at the other end to. a. counterweight 24, and operates to actuate the'rheostat 12. By means of a pipe under pressure or a drain conduit 50. Con- 1 necting pipe 10 with pipe 49 is a branch plpe 35 containing arestriction 36 of much smaller area than the orifice of nozzle 9.

Fig. 2 shows the relay 7 on enlarged scale, and it may be clearly seen therefrom how the member 14 isassembled of several and interconnected threads 30. In order that all the threads co-cperate it is necessary that all be under uniform tension, and the best method of constructing the strand is by winding the desired number of turns on two arallel combs, and attaching a rubberized inen strip about both'ends of the strand.

By this means the interval between the threads and their distance is accurately mounted in the clamps 25. The upper clamp is attached by means of the screw 26 to the nut 27, thus rendering possible an easily accessible, accurate ad uStment of the .regulating device.

For regulating the temperature of the air flowing through the room, a so-called. thermo relay 37 is provided, which is shown at operating servo-motor 38. This operation may be the same as with the humidity regulator. By means of the restriction 39, pressure changes in pipe 53 cause pressure changes'in the servo-motor which aetuates valve 32 mounted in the steam pipe 31 leading to the heating element 6. In the thermo relay a strip of ebonite 54 is used inplacepf the cotton threads 14 of the humidity rei 1 The operation of the apparatus is. as folows Suppose, for example, the room 2 is filled with wood to be dried. Atfirst a great deal of moisture is given 01f by'the. wood, as a. result. of which the humidity in the room in.-

maintained, .and the strand may easily be servo-motor 11 is connected with discharge pipe 50. counterweight 24 then outbalances pressure of liquid in the servo-motor and rotates rheostat 12 to increase the speed of fan 3 in order to hold the humidity constant. Now, when the speed of fan 3 is increased, the amount of air passing by and heated by the radiator 6 is also increased, so"

that the temperature of the same falls. This causes the tem rature regulatorto come into operation y decreasing the length of the temperature responsive element 54, thereby decreasing the pressure in pipe 53 and moving. valve 32 to o n the same. More steam 1s then admitted to the heating element 6 and the temperature of the air increased. As the wood becomes drier the amount of moisture given off is progressively less and less and the humidity relay causes the speed of fan 3 to decrease proportionally. This causes the air passing through heating element 6 to diminish in similar manner and the thermo relay operates to decrease the flow of steam in proportion. Thus in operation constant humidit and constant temperature are maint-aine andas the humidity is altered the temperature is altered accordingly.

Specific parts of the relay herein disclosed are claimed in my copending application Serial No. 719,022, filed June 9, 1924.

Having thus described my invention, what I claim is I a 1. In combination, a temperature and humidity controllingapparatus comprising a relay, means to dlscharge a continuously flowing stream of liquid into said relay, means to control said stream of liquid in response to humidity,.- means whereb said stream of liquid controls a current 0 air, a

' second relay,'means ;to discharge a continuously flowing stream of liquid mtosaid second relay, temperature responsive means to control. said second stream of liquid and means whereby the last mentioned continu:

ously flowing stream of liquid controls the temperature of said current of air.

, 2. In combination, a room, means to pass air through said room, 1i uid pressure operated means to control said means, a mechanism includin a continuously flowing stream of ii ui to control said liquid pressure operate a means, a humidity responsive device responsive to changes of humidity in lay, a mem theair'passing thru the room to control said continuously flowing stream of liquid, a heating element arranged to heat the air passing thru said room, liquid ressure operated means to control said heating element, mechanism including a continuously flowing stream of liquid to control the lastmentioned liquid pressure operated means, and a temperature res onsive device operservo-motor to control said rheostat, a relay,-

means to discharge a continuously flowing stream of liquid in said relay, a lever to control said continuously flowlng stream of liquid, a series of humidity r nsive elements responsive to chan es of umidity in the air passing thru the c amber to operate said lever, a heating element arranged to heat the air passin thru said chamber, and means to control saidheating element in response to changes in temperature in the air passing thru said'chamber.

4. Humidity control apparatus comprising a relay,- means to dischar e a continuously flowing stream of liquid into said relay, a member to throttle said stream of liquid, a series of humidity responsive elements to operate said member, and means controlled by changes of pressure in said stream of liquid to regulate humidity.

5. Humidity {control apparatus comprising a rela a; conduit ischarging a. continuous ly owing stream of liquid mtosaid relay, a member to throttle said stream of liquid, an element changeable in response to variations in humidit? acting on said member and means contro led by changes of pressure in said stream of liquid to regulate humidity.

6. Humidity control apparatus comprising a fan, an electric motor to drive said fan, a rheostat to control said motor, a. relay, a conduit discharging a continuously flowing stream of liquid into said relay, a member responsive to changes in humidity to throttle said stream of liquid, and means to adjust said rheostat in response to changes of pressure in said continuously flowing stream of liquid.

7. Humidity control ap 'aratus comprising a relay, means to disc arge a continuously flowm stream. of liquid into said reto throttle said stream of liquid, an. element changeable. in response to variations in humidit'y'acting on said member; means to adjust said element to vary the relation of said member to said stream of liquid for a givenvalue of humidity, and means controlled by changes of prescontrolled by said humidity responsive de- 7 sure in said stream of liquid to regulate vice to adjust said rheostat in accordance humidity. with changes in humidity. 10 8. A room, a fan operating to pass a cur- -In testimony whereof I hereunto aflix my 6 rent of air through said room, a rheostat to signature.

control said fan, a humidity responsive device and a liquid pressure operated member RAGNAR CARLSTEDT. 

